1. Field of the Invention
The present invention relates to a substrate processing method and a substrate processing system, and more particularly, to a substrate processing method for removing a hard mask and a deposit film from a substrate, and a substrate processing system for implementing the substrate processing method.
2. Description of the Related Art
A semiconductor wafer W as shown in FIG. 7 has been known, which has a single-crystal silicon substrate base 71 on which a thermally-oxidized film 72 made of SiO2, films 73, 74, and an oxide film such as a BPSG (boron phosphorous silicate glass) film 75 are formed in layers. To form a hole or a trench (groove) in the single-crystal silicon substrate base 71 of the wafer W, the silicon substrate base 71 is dry-etched in a depressurized environment using a plasma generated from a halogen-based processing gas such as an HBr (hydrogen bromide) gas and using the BPSG film 75 as a hard mask. At that time, the plasma reacts with silicon (Si) and as a result, a deposit film 76 of SiOBr is formed on a surface of the hole or the like. The deposit film 76 functions to suppress the single-crystal silicon substrate base 71 from being dry-etched.
The BPSG film 75 and the deposit film 76 of the wafer W can cause a conduction failure of a semiconductor device fabricated from the wafer W, and therefore these films must be removed. To remove the hard mask such as the BPSG film 75, a wet etching is employed (see for example, Japanese Laid-open Patent Publication No. 2005-150597).
Since a wet etching uses a chemical solution, a wet etching apparatus cannot be installed on the same substrate processing system together with a dry etching apparatus for dry-etching wafers W in a depressurized environment. In other words, the wet etching apparatus must be installed at a location different from the dry etching apparatus. Furthermore, the wafer W having been formed with a hole or the like in its single-crystal silicon substrate base 71 using the dry etching apparatus must be transferred out from the dry etching apparatus and then transferred in the ambient air before it is transferred into the wet etching apparatus. As a result, the substrate processing process is made complicated.
Moreover, the deposit film 76 made of SiOBr of the wafer W can react with the moisture content of the ambient air during the transfer of the wafer W in ambient air. Thus, it is necessary to manage a time period (Q-Time) during which the wafer W is exposed. More specifically, the exposure time period must be shortened to a minimum. The management of the exposure time period requires considerable man-hours.
In other words, the removal of the BPSG film 75 and the deposit film 76 causes a reduction in productivity of the fabrication of semiconductor devices from wafers W.